Briquetting die set



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INVENToR.

cz//er Nov. 24, 1959 J, HL'LER 2,913,766

` BRIQUETTING DIE sm Filed Feb. 11, 1957 3 sheets-sheet` 2 zizi? United Stes Patent O BRIQUETTING DIE SET John Haller, Northville, Mich.

Application February 11, 1957, Serial No. 639,382

2 Claims. (Cl. 18-34) This invention relates to powder metallurgy and, in particular, to briquetting devices for compacting masses of powdered metal into predetermined shapes which are subsequently sintered into durable sintered powdered metal workpieces.

One'object of this invention is to provide a briquetting die set which is capable of compacting powdered metal masses into precisely-shaped briquettes of substantially equal density throughout in any type of press, whether mechanical or hydraulic, the briquettes upon sintering becoming strong powdered metal workpieces.

Another object is to provide a briquetting die set of the foregoing character having a self-contained springfloated die unit which includes an upper die member or die holder adapted to receive interchangeable dies with open-ended die bores therein and floatingly-mounted upon springs resting upon a lower die member or die member support and receiving a lower punch or die bottom vmember so that as the upper punch attached to the press platen descends into the die bore and compresses the powdered metal charge therein, the frictional engagement of the charge with the s ide surface of the die bore transmits the downward force and motion of the upper punch to the upper die member and thereby causes the upper die member to be forced downward toward the lower die member by compressing the mounting springs between them.

Another object is to provide a briquetting die set of the foregoing character wherein the lower die member of the die unit has a threaded bore threadedly receiving a hand wheel or the like connected to the lower end of the die bottom member which in turn slidably engages the lower portion of the die bore in the upper die member whereby to enable a precise upward or downward adjustment of the die bottom member in the die bore or cavity so as to precisely adjust the height of fill of the powdered metal charge therein.

Another object is to provide a briquetting die set of the foregoing character especially adapted for producing tubular powdered metal briquettes for correspondingly tubular workpieces, the die bottom member of the die unit in this instance being tubular and longitudinallyslotted to receive a central core member supported by a transverse supporting rod, the opposite ends of which extend outward through the longitudinal slots into brackets secured to the upper die member.

Another object is to provide a briquetting die set of the foregoing character wherein the upper punch unit and the upper die member of the die unit are adapted to receive interchangeable punches and dies, the die inserts having a standard outer shape but with variously-shaped die bores or cavities so that the same die set is adapted to turn out briquettes for a wide variety of sintered powderedmetal workpieces, the die set thus being especially well adapted for use in small shops or in laboratories whereI it is desired to produce small experimental or test parts of varying shapes with a minimum of equipment and with any available type' of press.

Patented Nov. 24, v1959 ICC Another object is to provide a shielded briquetting die set of the foregoing character :wherein the upper die member of the die unit and/or the upper punch of the upper punch unit are provided with safety shields which can be moved into position after the filling of the die cavity with powdered metal but prior to the compression of the charge, so as to intercept any ying fragments of metal which might occur if the apparatus burst accidentally under the tremendous pressures occasionally used in compacting procedures, specially under experimental or laboratory conditions.

Other objects and advantages of the invention will become apparent during the course of the following description of the accompanying drawings, wherein:

Figure l is a top plan view of Ithe spring-floated die unit of a briquetting die set, according to one form of the invention, with the upper punch unit omitted, looking in the direction of the line 1 1 in Figure 2;

Figure 2 is a central vertical section through the die set of Figure l including the punch unit, taken upon the circuitous section line 2 2 therein showing the oating springs for the upper die member upon the lowerdie member;

Figure 3 is .a central vertical section through the die set of Figure l, taken along the circuitous section line 3 3 therein, showing the guide and limit stop devices between the upper and lower die members;

Figure 4 is a side elevation of the lower portion of the die set shown in Figure 2, showing in side elevation the cylindrical lower shield and one of the bayonet slots by which it is movably supported upon the upper die member;

Figure 5 is a horizontal section through the upper punch holder, punch and upper shield, taken along the line 5 5 in Figure 3;

Figure 6 is a top plan view of a die set generally similar to that of Figures l to 5 inclusive, but provided with a tubular lower punch and with a core member for producing tubular workpieces;

Figure 7 is a central vertical section through the die set of Figure 6, taken along the circuitous section kline 7 7 therein;

Figure 8 is a horizontal section taken along the line 8 8 in Figure 7, in the plane of the supporting rod for the core member; and

Figure 9 is a fragmentary central vertical section taken along the line 9 9 in Figure 6, showing one of the limit stop devices'- Hitherto, the production of small briquettes or molded or compacted powdered metal shapes afterward transformed into sintered powdered metal workpieces by sintering the briquettes has been difficult in small shops or in laboratories, especially Where it is desired to achieve a substantially uniform density throughout the workpiece, because of the absence of the large and complicated hydraulic or mechanical presses capable of producing such workpieces. Moreover, it has also hitherto been diicult in such shops and laboratories to produce the Wide variety of workpieces called for under experimental or test conditions because of the necessity of keeping the shop or laboratory equipment and investment within reasonable or feasible limits. The present invention provarious interchangeable punches and dies adapted to turn out compacted briquettes in a wide variety of shapes and sizes and of substantially uniform density, this single die set being also capable of being used in any type of suitable available press, whether hydraulic or mechanical. Removable shielding means is also optionally provided for protecting the operator from injury by flying fragments which might occur under excessively-high presa sures `of compacting, such as might arise in experimental work in powder metallurgy in producing experimental or test specimens.

Referring to the drawings in detail, Figures 1 to 5 inclusive show a spring-oated briquetting die set, generally designated 10, consisting generally of an upper punch unit 12 and a die unit 14 containing a die 1S suitably bored to receive and mate with the punch of the punch unit 1 2. The die set 10 is adapted to be used in any type of suitable press (not shown), either hydraulic or mechanical, with the punch unit 12 connected to the press platen and the die unit 14 mounted on and supported by the press bed. Suitable presses for this purpose are wellknown to workers in the powder metallurgy eld and are available in wide varieties, both mechanical and hydraulic, upon the press market.

The punch unit 12 consists of a punch carrier or shield carrier, generally designated 16 (Figures 2, 3 and 5) of any suitable shape, according to the shape of the workpiece to be produced, here shown in the form of a rectangular block containing a socket 1S of elongated cross-section (Figure into which ts the correspondingly-shaped upper end portion of an upper punch, generally designated 20, the latter being drilled and threaded as at 22 to receive the correspondingly-threaded shanks of machine screws 24 seated in countersunk bores 26 in the punch carrier 16 and holding the punch 20 firmly in its socket 18. The upper punch 20 is of any suitable cross-section according to the cross-section of the workpiece to be produced, the cross-section shown in Figure 5 being shown solely for purposes of illustration and not by way of limitation.

The punch carrier 16 on its opposite sides is drilled and threaded as at 28 to receive the shanks of machine screws 30, the heads of which slidably and guidingly engage the sides of elongated vertical slots 32 in the side walls 34 of a cup-shaped upper shield, generally designated 36, the latter containing a cavity 38 which is shaped to telescope with the punch carrier 16 in relatively sliding engagement. T'ne bottom wall 40 of the shield 36 is provided with a central aperture 42 of similar cross-section to the cross-section of the upper punch 20 with sucient clearance therebetween to provide for free upward and downward travel of the shield 36 relatively to the upper punch 20. The shield 36 contains compression springs 42 disposed between the bottom wall 40 and the bottom of the punch holder 16 within the cavity 38 thereof, so as to urge the shield 36 downwardly yet yieldable relatively to the upper punch 2t). In Figure 3, the shield 36 is shown for convenience in an intermediate position between the upper and lower limits of its stroke as regulated by the engagement of the heads of the screws 30 with the upper and lower ends of their guide slots 32. As previously stated, the punch carrier 16 is secured to the press platen (not shown) by any suitable means, such as by bolts or clamps, forming no part of the present invention.

The self-contained spring-floated die unit 14 of the die set consists generally of an upper die member or die holder 44, an annular lower shield adapter 46, a sleeve-shaped lower shield 48, a lower die member 50, a die bottom member S2, a die bottom adjustment 54, and a die bottom holder 56 above the latter and connected thereto. The lower shield adapter 46 is drilled and threaded radially as at 57 to receive the threaded shank portions of guide screws 58. The Unthreaded shank portions of the guide screws 58 in turn slidably engage L-shaped bayonet slots 60 (Figure 4) in the sleeveshaped lower shield 48. The bayonet slots 60 have lower horizontal portions 62 and upper vertical portions 64 which selectively engage the unthreaded shank portions of the guide screws 58 when the lower shield 48 is respectively raised (Figures 2, 3 and 4) or lowered. This raisingrandlowering of the shield 48 is accomplished by ,Vi-means -of handles 68 having threaded VShanks .70

ber 50.

4 threaded into correspondingly-threaded diametrically opposite holes 72 in the shield 46.

The annular lower shield adapter 46 is secured to the upper die member or die holder 44 in any suitable way, as by screws (not shown). It is optional and may be omitted along with the upper shield 36, as shown in Figures 6 to 9 inclusive, where the character of the work or procedure is such that accidents and ying fragments are unlikely to occur.

The upper die member or die holder 44 is provided with a central recess 74 which is preferably of circular crosssection and closed at the bottom by a bottom wall 7S so as to receive any one of a variety of dies, generally designated 76, adapted to mate with their corresponding punches 20. For this purpose, the die 76 has a die cavity of die bore 78 of corresponding cross-section to the upper punch 20 and of such size as to snugly but slidably receive the upper punch 20 during the vertical reciprocation thereof. The die holder 44 and the die 76 are drilled from the bottom with aligned holes 80 and 82 for the reception of screws 84 inserted through the holes 80 and threaded into the threaded holes 82 for retaining the die 76 within the recess 74 (Figure 3). The die holder 44 is also provided with downwardly-facing sockets 84 (Figure 2) preferably spaced at equal intervals around the circumference, four such sockets being employed for convenience. Seated in the downwardlyfacing socket 84 are the upper ends of helical compression springs 86, the lower ends of which are seated in aligned upwardly-facing sockets 8S in the lower die mem- Interposed between the upper spring sockets 84 -in the die holder 44 are two diametrically-opposite downwardly-facing guide pin sockets 90 (Figure 3) in which are seated the upper ends of cylindrical guide pins` 92, the lower ends of which are snugly but slidably received in aligned vertical guide pin bores 94 in the lower die member 50.

Also interposed between the spring sockets 84 in the die holder 44 ninety degrees away from the guide pin sockets 90 are two other diametrically-opposite downwardly-facing threaded stop pin bores 96 receiving the threaded upper ends 98 of stop pins 100 reciprocably engaging aligned vertical bores 102 in the lower die member and having heads 104 reciprocably engaging enlarged counterbores 106 therein, the annular shoulder 108 between each bore 102 and counterbore 106 servl ing as a stop shoulder for limiting the upward travel of the upper die member or die holder 44 under the thrust of the floating springs 86.

The lower die member 50 is provided centrally with a cylindrical vertical smooth bore 110 and a coaxial threaded counterbore 112 which respectively receive the cylindrical bottom holder or support 56 (Figures 2 and 3), the bore 110 being of such diameter as to accommodate the largest diameter of the die bottom member S2, also occasionally known as the lower stationary punch or xed punch. The latter in its lower end is provided with threaded screw holes 116 aligned with corresponding smooth countersunk holes 118 for receiving screws 120 (Figure 2) by which the die bottom member 52 is secured to the die bottom holder 56. The latter in turn is provided centrally with a threaded hole 122 aligned with a countersunk central bore 124 in the die bottom adjustment member 54 and adapted to receive a headed pivot screw 126 having its threaded shank seated in the threaded bore 122, thereby mounting the die bottom adjustment member 54 rotatably upon the pivot pin 126 for rotation relatively to the dievbottom support 56. The die bottom adjustment member 64 is provided with a threaded cylindrical body or shank 128 threadedly engaging the threaded counterbore 112 and having a circular head or flange 130 provided with Spanner sockets 132 (Figure 2) for the reception of a conventional spanner or other suitable wrench for rotating the die ,bottom adjustment member 54. ,The lower die member l50 isV provided with similar spanner sockets 134 for similarly other to raise or lower the die bottom support 56` and consequently to raise or lower the die bottom or fixed punch 52 relatively to the die 76 within the die bore 78, so as to vary the height of ll of the diebore 78.

Self-contained briquettz'ng die set for tubular workpeces The self-contained briquetting die set, generally designated 140, shown in Figure 7 is generally similar to the die set 10 of Figure 2 except that the upper and lower shields 36 and 48 have been omitted, together with the lower shield adapter 46, and also that the device is arranged to turn outtubular workpieces rather than solid workpieces. Since the die set 140 generally resembles the die set 10 in the major part of itsconstruction, similar parts bear the same reference numerals in order to avoid unnecessary duplication of description.

The die set 140 consists generally of a flanged tubular upper punch 142, and a die unit 144, the latter including similar upper and lower die lmembers 44 and 50 to those of Figures 1 to 5 inclusive, and likewise a similar die bottom adjustment member 54 and a die bottom holder or support 56 connected thereto by a similar pivot screw 126. Similar compression springs 86, guide pins 92 and stop pins 100 are disposed in a similar manner between the upper and lower die members 44 and 50 and act in a similar manner to that described above in connection with Figures l to 5 inclusive.

The upper punch 142 has a bore 146 therein adapted to enter the die bore 148 in the die 150 between it and the side surface 152 of a core member 154, these in cooperation with one another forming an annular die cavity 156. The recess 74 in the upper die member or die holder 44, however, is closed at the bottom by a separate bottom wall member, generally designated 158, sealed in a counterbore 160 in the upper die member 44. The latter and the bottom wall member 158 are drilled and threaded to receive screws 162 holding these parts together. The bottom wall member 158 is provided with a central bore 164 of substantially the same diameter and coextensive with the die bore 148 so that both receive a tubular upstanding die bottom member, generally designated 166 (Figure 7). The core member 154 is held in position and retained in association with the upper die member 44 by being drilled transversely as at 168 to receive a cross pin 170, the opposite ends of which pass through elongated vertical slots 172 in the opposite sides of the die bottom member 166 and are seated in aligned transverse bores 174 in the depending portion 176 of the bottom wall member 158. The die bottom holder 56 and the bottom member 166 are respectively drilled and threaded to receive the screws 120 as in Figure 2 and the die bottom holder 56 is also drilled and threaded at 122 as before to receive the pivot pin 126, a cavity 178 being provided therein above the screw hole 122 to provide clearance for the lower end of the core member 154.

Operation In the operation of the die set of Figures l to 5 inclusive, the punch unit 12 is secured to the platen of any type of suitable press, and the die unit 14 mounted on the bed thereof with the lower die member 50 resting upon the press bed and the upper die member 44 oating thereon by means of springs 86. The lower die member 50 is, of course, clamped in position to prevent displacement by suitable clamping means (not shown) so that the die bore 78 remains accurately in alignment with the punch 20. With the press platen and consequently the punch 20 in their raised positions, and with the die bottom or lower punch 52 moved upward in the die bore 78 by means of the adjusting member 54 to give the desired height of lill, the die bore '.78 is charged with the suitable powdered material, such as powdered metal, by any conventional charging means. By means of the handles 68, the cylindrical shield- 46 is lifted and then rotated circumferentially so that the pins 58 are seated in the horizontal portions 62 of the bayonet slots 60 (Figure 4).

The press is then operated to cause the punch unit 16 and its punch 20 to descend and enter the die bore 78, compressing the charge of powdered material. As the charge of powdered material becomes compacted, it frictionally engages the side walls of the die bore 78 more rmly, this friction finally causing the force and downward motion of the upper punch 20 to be transmitted through the powdered material to the die 76 and thence to the upper die member or die holder 44, moving it, the adapter 46 and the shield 48 downward as a unit, compressing the springs 86 upon which this assembly floats. Meanwhile, the lower edge of the upper shield 36 engages the upper surface of the die 76 so as to entrap any flying fragments which might occur in the event of breakage. Any fragments not caught by the upper shield 36 are intercepted by the lower shield 48, which is now in its raised position. This floating action and gradual downward motion of the upper die member 44 toward the lower die member 50 causes the briquette to be compacted with a substantially uniform density throughout.

Ejection or" the workpiece is then accomplished by retracting the press platen and punch unit 12 upward, followed either by moving the die bottom S2 upward by rotating the hand wheel or adjustment member 54 to cause its body or barrel with the threads 128 to move upwardly in the threaded bore 112, or by the use of any suitable depressing device to depress the upper assembly of the upper die member 44 and die 76 after having lowered the shield 48 to permit access to the upper surface thereof. In either case, the briquette is expelled from the die cavity 78, whereupon a new charge of powdered material is placed thereon and the foregoing procedure repeated indefinitely.

During the foregoing operation, moreover, as the upper assembly consisting of the die holder 44, adapter 46, shield 48 and die 76 move downwardly, they are guided by the guide pins 92 in the bores 94 (Figure 3) and by the stop pins in the bores 102 and counterbores 106. When the upper assembly returns to its raised position upon the raising of the press platen and upper punch unit 12, the heads 104 of the stop pins 100 engage the annular shoulders 108, halting the upward travel at the desired location.

The operation of the modified die set of Figures 6 to 9 inclusive, is generally similar to thatgalready described in connection with the operation of the die set 10, except that the charge of powdered material is tubular and the core member 154 travels downwardly with the die and die holder 44 while the springs 86 are being compressed. The elongated slots 172 permit the tubular die bottom member 166 to remain stationary during this downward motion. The expulsion of the brquette takes place in the same way and the procedure is otherwise identical.

What I claim is:

1. A self-contained shielded briquetting die set for mounting in a conventional press having a platen and a bed comprising a punch unit including a punch holder adapted to be attached to the conventional press platen, a die unit including a die holder support adapted to be mounted on the conventional press bed, a die holder disposed in spaced relationship to said support, resilient die holder floating means disposed between said die holder and said support, and a guiding aligning device disposed between said support and said die holder in guiding aligning relationship therebetween, one of said holders having a iirst outer bearing surface thereon and a first shield including a first tubular member having a substantially solid side wall reciprocably mounted Qn 71 said last-mentioned holder in encircling relationship therewith, said rst shield having a first bearing bore of mating configuration to said first bearing surface in telescoping engagement therewith and movable relatively thereto upon engagement with the other holder, the other holder having a substantially cylindrical second outer bearing surface thereon and a second shield including a second tubular member having a substantially solid side wall mounted upon the other holder in encircling relationship therewith, said second shield having a substantially cylindrical bore telescopingly engaging said second bearing surface, said second shield being of sufficiently different diameter than said first shield for approximate telescoping relationship with said rst shield, said second shield being of lesser height than the overall height of the unit of the holder to which it is attached whereby to permit sliding of said second shield axially relatively to its respective unit during use without interference from the press and without interfering with the press, said second shield being movably mounted on said References Cited in the le of this patent UNITED STATES PATENTS 2,336,982 Cremer Dec. 14, 1943 2,338,491 Cutler Jan. 4, 1944 2,415,462 Cherry et al. Feb. 11, 1947 2,653,377 Seclig Sept. 29, 1953 

